1. Field of the Invention
The present invention relates generally to an inventive approach for improving the interfacing of connections between a multiplicity of handheld electronic units such as cell phones, etc. that may have the need for add-on units to be connected thereto. Such devices may include barcode scanners, PDAs, printers, scanners, and the like.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Hand held units such as computers, cell phones, personal digital assistants (PDAs) etc are becoming increasingly useful amongst consumers and industry. In certain applications, such hand held units may utilize the RS232 standard, a standard which has been in existence since 1969, yet it is still used in many types of equipment manufactured today. In such applications, the RS232 standard may be utilized for serial binary data signals connecting between DTEs (Data Terminal Equipment) and a DCEs (Data Circuit-terminating Equipment).
Usually in such applications, a given DTE device may be established as the terminal while the DCE may be a modem, where a “null” modem scheme is employed as a communication method to connect two DTEs directly using a cross-linked connection between transmit (TX) and receive (RX) lines in RS232 serial cable. In doing so, many DTEs have eliminated the various signals defined in the standard and reduced the interface to a three wire interface using TxD (transmitted data), RxD (received data) and Ground. One such application is the R232 serial interface available on mobile terminals such as cellular phones and PDAs. This interface can be used to communicate with other devices on a three wire connection, however known systems in this regard offer significant drawbacks, not the least of which is the fact that the RS232 scheme is a point to point communication protocol whereby multiple devices (especially three or more devices) cannot communicate at the same time.
Prior art attempts to address such limitations may be seen in documents such as U.S. Pat. Nos. 4,607,379, 5,675,524, and 5,497,339, each of which are hereby incorporated by reference in their entireties, offer only crude solutions for attempting to establish device connections interfaces for sending data. To this end, related prior art solutions have been hitherto limited to the provision of point-to-point communication between separate RS232 ports, without the ability to seamlessly connect more than two devices, given that there are no additional signal lines available in the RS232 standard. Given the various drawbacks related to the usage of a point-to-point set-up such as RS232, there is clearly a need to provide for a more simplified, single RS232 port system that works within the limitations of multiple connectivity set-ups, without the any drawbacks. As such, it would be most desirable if only one problem-free interface could be capable of establishing RS232-type communications between a base unit and two, three or more additional devices while using only one common port.